静压下半导体微腔内激子与光子行为的研究

由于腔模与激子对压力的依赖关系不同,所以可以选择不同的压力使激子和光场处于不同的耦合状态,从而实现对耦合的调谐。利用这种办法,我们观测到了代表激子与光场强耦合作用的Rabi分裂。由于在我们现有样品结构中压力对激子本征行为的影响很小,与以前报道的温度、电场等调谐方式相比,这种调谐方法不仅可以有效地调谐半导体微腔内激子与腔模的耦合程度,而且能够保持激子的本征性质在整个调谐过程中基本不变。这有助于研究在强耦合过程中激子极化激元的本征性质。将实验结果与压力下激子与腔模耦合理论进行拟合,得出了正确的Rabi分裂值。     

Laterally Confined Modes in Wet－Etched, Metal－Coated, Quantum－Dot－Inserted Pillar Microcavities

We report the fabrication and the measurement of microcavities whose optical eigenmodes were discrete and were well predicted by using the model of the photonic dot with perfectly reflected sidewalls. These microcavities were consisted of the semiconductor pillar fabricated by the simple wet-etched process and successive metal coating. Angle-resolved photoluminescence spectra demonstrate the characteristic emission of the corresponding eigenmodes, as its pattern revealed by varying both polar (θ) and azimuthal ( φ) angles. It is shown that the metal-coated sidewalls can provide an efficient way to suppress the emission due to the leaking modes in these pillar microcavities.     

三势垒隧穿结构中由外加垂直磁场引入的高子带非热占据

在一个特殊设计的三垒双阱异质结构中 ,注入到入射端量子阱中的电子 ,首先经过子带间弛豫填充到较低能级 ,紧接着通过共振隧穿逃逸出后面的双势垒结构 ,流入收集电极 ,完成了整个输运过程。通过比较带间光荧光谱中E2 HH1 与E1 HH1 两峰的强度 ,我们发现外加垂直磁场可以抑制子带间的LO声子和LA声子散射 ,使能量较高的子带上出现了明显的非热平衡占据。这一发现提供了一种新的控制子带间散射速率 (量子级联激光器的主要机制 )的有效方法 ,使得在量子阱子带间实现粒子数反转变得更加容易。